Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd Deal Finder...
Buy other stuff at Amazon.com...
Capacities up to 48TB and speeds up to 1527MB/s

About RAID

Last updated 2014-01-04 - Send Feedback
Related: backup, RAID, RAID-5, storage

RAID can be implemented in hardware or software.

Most computer users do not use RAID at all, using instead independent hard drive or SSD storage. That approach is least expensive and fine for most uses.

RAID is not for backup

The fault tolerant aspect of some types or RAID should not be confused with a proper backup strategy.

It’s not that RAID (e.g., a mirror) is a bad idea for backup, rather, it is generally a waste of money and a reduction in redundancy: it is always better to have multiple independent redundant backups than one RAID backup.

For example, two independent backup drives of 4TB each are better than one RAID-1 mirror single unit. In the dual case, failure of one unit leaves the other intact and they can be stored separately, further reducing risk; in the single-unit RAID-1 case, loss of the unit means all is lost (consider theft, fire, flood, etc).

Why use RAID?

For professionals, higher performance and/or fault tolerance might be helpful or even essential, and that is where RAID comes into the picture.

RAID compared using four 4TB drives
  RAID-5 RAID 1+0 RAID-0 stripe RAID-1 mirror RAID SPAN JBOD
# Drives 4 4 4 4 4, concatenated 4
independent
non-RAID
Capacity: 12TB 8TB 16TB 4TB 16TB 16TB
Fault tolerance: single failure OK single failure OK
from each mirror
single failure kill volume three failures OK single failure kills volume independent
Read Speed ~3X 2X 4X 1X 1X, variable 1X
Write Speed 2.2X - 3X 2X 4X 1X 1X, variable 1X

Relative performance of RAID- vs RAID-5

See RAID-5 vs RAID-0 performance.

ThunderTek/PX Q6G: RAID-0 striping vs RAID-5

 

 


B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 22 hours unless noted. Certain deals may last longer.
$3199 SAVE $200 = 5.0% $99 FREE ITEMS Canon EOS R Mirrorless with 24-105mm in Cameras: Mirrorless
$1632 SAVE $700 = 28.0% $165 GIFT CARD LG C8PUA 55" Class HDR UHD Smart OLED TV in Electronics: Televisions
$3097 SAVE $200 = 6.0% $78 FREE ITEMS Nikon D850 DSLR in Cameras: DSLR
$1797 SAVE $200 = 10.0% Pentax K-1 Mark II DSLR in Cameras: DSLR
$998 SAVE $400 = 28.0% Sony a7 II Mirrorless in Cameras: Mirrorless
$1798 SAVE $200 = 10.0% Sony a7R II Mirrorless in Cameras: Mirrorless
$3998 SAVE $500 = 11.0% Sony a9 Mirrorless in Cameras: Mirrorless
$5987 SAVE $1839 = 23.0% ZEISS Loxia 5-Lens Bundle in Lenses: Mirrorless
$11594 SAVE $3157 = 21.0% ZEISS Otus ZF.2 3-Lens Bundle in Lenses: DSLR

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2019 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__